Optimized sealing device for a bearing unit

A bearing unit having an axis of rotation (X), comprising:

• a flanged first radially inner, rotatable, ring;
• a radially external, stationary, ring;
• a second radially inner ring, rotatable, mounted on and integral with the flanged first radially inner ring;
• a plurality of rolling bodies interposed between the radially outer ring and both the first and second radially inner rings;
• and
• a sealing device comprising:
• a stationary part comprising:
• a first metal screen comprising:
• an annular shaped portion;
• and
• a cylindrical portion, wherein the cylindrical portion is radially external with respect to the annular shaped portion;
• an elastomer coating comprising:
• an annular shaped elastomeric portion;
• a cylindrical elastomeric portion;
• a contacting lip radially internal with respect to the cylindrical elastomeric portion and axially external with respect to the annular shape elastomeric portion;
• and
• a first non-contacting lip extending radially and internally from the cylindrical elastomeric portion,
• wherein the elastomer coating is co-moulded on the first metal screen in a radially external position with respect to the first metal screen,
• a rotatable part comprising:
• a second metal screen comprising:
• a first portion extending radially;
• and
• a radially outer wing,
• wherein the contacting lip is configured to make sliding contact with the second metal screen,
• the radially outer wing and the first non-contacting lip define a first radial labyrinth seal,
• a first pre-chamber is defined between the first metal screen, the annular shaped elastomeric portion, and the contacting lip, and
• a radially outer surface of the radially outer wing of the second metal screen is radially flush with an outer radial surface of the radially outer ring.

A bearing unit, comprising:

• a flanged first radially inner, rotatable, ring;
• a radially outer, stationary, ring;
• a second radially inner ring, rotatable, mounted on, and integral with the flanged radially inner ring;
• a plurality of rolling bodies interposed between the radially outer ring and both the first and second radially inner rings;
• and
• a sealing device disposed in a cavity defined by the flanged first inner ring and the outer ring, the sealing device comprising:
• a first metal screen affixed to the radially outer ring, comprising:
• an annular shaped portion;
• and
• a cylindrical portion, the cylindrical portion being radially external with respect to the annular shaped portion;
• an elastomer coating comprising:
• an annular shaped elastomeric portion;
• a cylindrical elastomeric portion;
• a contacting lip radially internal with respect to the cylindrical elastomeric portion and axially external with respect to the annular shaped portion;
• and
• a non-contacting lip extending radially and internally from the cylindrical elastomeric portion wherein the elastomer coating is co-moulded on the first screen and positioned radially external and axially external with respect to the first metal screen;
• a c-Shaped second metal screen comprising a radially outer wing and affixed to the flanged first radially inner ring,
• wherein the contacting lip is configured to make sliding contact with a surface of the c-shaped second metal screen,
• the radially outer wing of the second metal screen and the non-contacting lip define between them a first radial labyrinth seal,
• an annular surface of the flanged inner ring, a cylindrical surface of the flanged inner ring, a connecting radius connecting the annular surface of the flanged inner ring the cylindrical surface of the flanged inner ring, the c-shaped metal screen, and the cylindrical elastomer portion define between them a cavity configured to contain and expel contaminants by subjecting the contaminants to vertical motion during use, and
• a volume of the cavity is proportional to a length of the connecting radius.